Reading Battery Data With an Arduino

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Glad some other people are making progress! I managed to kill my OLED screen somehow so haven't got much further!

@dneelands - if you haver some copper tape, I made some pretty reliable connectors using cut up credit card, adding a few extra layers of copper tape until the connection was tight, but not too tight. Until I did this I had very unpredictable results just by jamming wires in.
I started trying to use an old display from a megapilot APM setup but it was dead. Those little strips were cheap and I am hoping with the nano they'll make a nice compact package.

I do have a bunch of tape from making GPS shields. How do you connect to the tape? I haven't tried soldering it. Of couser where you solder would lose glue.
 
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Here's the code and what it should look like, with added splash screen!

I've chosen only to display the information I'm interested in - I am not planning on using this whilst charging so that info is available but ignored.

I'd still like to sort out the cell voltages which are currently in mV not V as my code was truncating the full voltages from 4 to 2 decimal places - easy enough to fix it but was getting tired.

Might also add a button or 2 to enable scrolling between the different screens, any other suggestions welcome :)

The small change I had to make to my setup was moving back to the 4.7K resistors instead of the 10K ones that I was initially using on the basis that I needed a higher value due to having 2 devices on the same I2C line. The other changes are visible in the code attached...


I have been playing with this again, Im stuck. Im stuck at LCD.init(); As soon as i use this to start talking to the LCD screen it will not read the battery any longer. This is why when i put it at the end of my Void loop(); It runs once outputs the battery data to the Serial and to the LCD one time. Then reads bogus data... Its because it messes with the i2C bus. I have no idea how to solve this. Here is my code. Anybody care to help me ? Thanks!


Code:
/**********************************

 * SMBus FOR 3DR SOLO
 * STAVROPOULOS
 * Code Version 0.01 beta
 *
 * MUCH OF THIS CODE WAS COPIED FROM
 * https://github.com/PowerCartel/PackProbe/blob/master/PackProbe/PackProbe.ino
 * https://github.com/ArduPilot/PX4Firmware/blob/master/src/drivers/batt_smbus/batt_smbus.cpp
 *
 **********************************/

/**********************************
 * CONFIGURE I2C/SERIAL ON ARDUINO
 **********************************/
 
//DEFINE SDA AND SCL PINS
  #define SCL_PIN 5                 //COMMUNICATION PIN 20 ON MEGA PIN5 on R3 UNO
  #define SCL_PORT PORTC

  #define SDA_PIN 4                 //COMMUNICATION PIN 21 ON MEGA PIN 4 on R3 UNO
  #define SDA_PORT PORTC

//CONFIGURE I2C MODES
  //#define I2C_TIMEOUT 100           //PREVENT SLAVE DEVICES FROM STRETCHING LOW PERIOD OF THE CLOCK INDEFINITELY AND LOCKING UP MCU BY DEFINING TIMEOUT
  //#define I2C_NOINTERRUPT 1       //SET TO 1 IF SMBus DEVICE CAN TIMEOUT
  //#define I2C_FASTMODE 1          //THE STANDARD I2C FREQ IS 100kHz.  USE THIS TO PERMIT FASTER UP TO 400kHz.
  //#define I2C_SLOWMODE 1            //THE STANDARD I2C FREQ IS 100kHz.  USE THIS TO PERMIT SLOWER, DOWN TO 25kHz.
  #define BAUD_RATE 115200
  #include <SoftI2CMaster.h>

/**********************************
 * CONFIGURE SERIAL LIBRARY
 **********************************/
  //#include <SoftwareSerial.h>
  //#include <Serial.h>
  #include <Wire.h>
  #include <LiquidCrystal_I2C.h> //i2c library for my LCD display that works.
 
 
/**********************************
 * DEFINE VARIABLES AND SMBus MAPPINGS
 **********************************/

  #define BATT_SMBUS_ADDR                     0x0B                ///< I2C address
  #define BATT_SMBUS_ADDR_MIN                 0x08                ///< lowest possible address
  #define BATT_SMBUS_ADDR_MAX                 0x7F                ///< highest possible address
//BUS MAPPINGS FROM DEV.3DR
  #define BATT_SMBUS_TEMP                     0x08                ///< temperature register
  #define BATT_SMBUS_VOLTAGE                  0x09                ///< voltage register
  #define BATT_SMBUS_REMAINING_CAPACITY       0x0f                ///< predicted remaining battery capacity as a percentage
  #define BATT_SMBUS_FULL_CHARGE_CAPACITY     0x10                ///< capacity when fully charged
  #define BATT_SMBUS_DESIGN_CAPACITY          0x18                ///< design capacity register
  #define BATT_SMBUS_DESIGN_VOLTAGE           0x19                ///< design voltage register
  #define BATT_SMBUS_SERIALNUM                0x1c                ///< serial number register
  #define BATT_SMBUS_MANUFACTURE_NAME         0x20                ///< manufacturer name
  #define BATT_SMBUS_MANUFACTURE_DATA         0x23                ///< manufacturer data
  #define BATT_SMBUS_MANUFACTURE_INFO         0x25                ///< cell voltage register
  #define BATT_SMBUS_CURRENT                  0x2a                ///< current register
  #define BATT_SMBUS_MEASUREMENT_INTERVAL_US  (1000000 / 10)      ///< time in microseconds, measure at 10hz
  #define BATT_SMBUS_TIMEOUT_US               10000000            ///< timeout looking for battery 10seconds after startup
  #define BATT_SMBUS_BUTTON_DEBOUNCE_MS       300                 ///< button holds longer than this time will cause a power off event
 
  #define BATT_SMBUS_PEC_POLYNOMIAL           0x07                ///< Polynomial for calculating PEC
  #define BATT_SMBUS_I2C_BUS                  PX4_I2C_BUS_EXPANSION
//BUS MAPPINGS FROM SMBus PROTOCOL DOCUMENTATION
#define BATTERY_MODE             0x03
#define CURRENT                  0x0A
#define RELATIVE_SOC             0x0D
#define ABSOLUTE_SOC             0x0E
#define TIME_TO_FULL             0x13
#define CHARGING_CURRENT         0x14
#define CHARGING_VOLTAGE         0x15
#define BATTERY_STATUS           0x16
#define CYCLE_COUNT              0x17
#define SPEC_INFO                0x1A
#define MFG_DATE                 0x1B
#define DEV_NAME                 0x21   // String
#define CELL_CHEM                0x22   // String
#define CELL4_VOLTAGE            0x3C   // Indidual cell voltages don't work on Lenovo and Dell Packs
#define CELL3_VOLTAGE            0x3D
#define CELL2_VOLTAGE            0x3E
#define CELL1_VOLTAGE            0x3F
#define STATE_OF_HEALTH          0x4F
//END BUS MAPPINGS
 
  #define bufferLen 32
  uint8_t i2cBuffer[bufferLen];

// standard I2C address for Smart Battery packs
  byte deviceAddress = BATT_SMBUS_ADDR;
 
  LiquidCrystal_I2C LCD(0x3B,16,2);
 
 
//int i2c;



           

void setup()
{

  //INITIATE SERIAL CONSOLE
    Serial.begin(BAUD_RATE);
  /*
    Serial.println(i2c_init());
   
   
  //SETUP I2C INPUT PINS
   // pinMode(5,INPUT_PULLUP);  // commented this out becauase it cant be used on R3 UNO
   // pinMode(4,INPUT_PULLUP);
    Serial.flush();

    while (!Serial) {
    ;                                                       //wait for Console port to connect.
    }

    Serial.println("Console Initialized");
 */
    i2c_init();                                             //i2c_start initialized the I2C system.  will return false if bus is locked.
    Serial.println("I2C Inialized");

 
 
}    

int fetchWord(byte func)
{
    i2c_start(deviceAddress<<1 | I2C_WRITE);                //Initiates a transfer to the slave device with the (8-bit) I2C address addr.
                                                            //Alternatively, use i2c_start_wait which tries repeatedly to start transfer until acknowledgment received
    //i2c_start_wait(deviceAddress<<1 | I2C_WRITE);
    i2c_write(func);                                        //Sends a byte to the previously addressed device. Returns true if the device replies with an ACK.
    i2c_rep_start(deviceAddress<<1 | I2C_READ);             //Sends a repeated start condition, i.e., it starts a new transfer without sending first a stop condition.
    byte b1 = i2c_read(false);                              //i2c_read Requests to receive a byte from the slave device. If last is true,
                                                            //then a NAK is sent after receiving the byte finishing the read transfer sequence.
    byte b2 = i2c_read(true);
    i2c_stop();                                             //Sends a stop condition and thereby releases the bus.
    return (int)b1|((( int)b2)<<8);
}

uint8_t i2c_smbus_read_block ( uint8_t command, uint8_t* blockBuffer, uint8_t blockBufferLen )
{
    uint8_t x, num_bytes;
    i2c_start((deviceAddress<<1) + I2C_WRITE);
    i2c_write(command);
    i2c_rep_start((deviceAddress<<1) + I2C_READ);        
    num_bytes = i2c_read(false);                              //num of bytes; 1 byte will be index 0
    num_bytes = constrain(num_bytes,0,blockBufferLen-2);      //room for null at the end
    for (x=0; x<num_bytes-1; x++) {                           //-1 because x=num_bytes-1 if x<y; last byte needs to be "nack"'d, x<y-1
      blockBuffer[x] = i2c_read(false);
    }
    blockBuffer[x++] = i2c_read(true);                        //this will nack the last byte and store it in x's num_bytes-1 address.
    blockBuffer[x] = 0;                                       //and null it at last_byte+1
    i2c_stop();
    return num_bytes;
}



void loop()
{


    uint8_t length_read = 0;
 
    //delay (750);
    Serial.write(12);
    Serial.print("Manufacturer Name: ");
    length_read = i2c_smbus_read_block(BATT_SMBUS_MANUFACTURE_NAME, i2cBuffer, bufferLen);
    Serial.write(i2cBuffer, length_read);
    Serial.println("");
 
    //Serial.print("Manufacturer Data: ");
   // length_read = i2c_smbus_read_block(BATT_SMBUS_MANUFACTURE_DATA, i2cBuffer, bufferLen);
    //Serial.write(i2cBuffer, length_read);
   // Serial.println("");
 
   // Serial.print("Manufacturer Info: ");
    //length_read = i2c_smbus_read_block(BATT_SMBUS_MANUFACTURE_INFO, i2cBuffer, bufferLen);
    //Serial.write(i2cBuffer, length_read);
   // Serial.println("");
 
    Serial.print("Design Capacity: " );
    Serial.println(fetchWord(BATT_SMBUS_DESIGN_CAPACITY));
 
    Serial.print("Design Voltage: " );
    Serial.println(fetchWord(BATT_SMBUS_DESIGN_VOLTAGE));
 
    Serial.print("Serial Number: ");
    Serial.println(fetchWord(BATT_SMBUS_SERIALNUM));
 
    Serial.print("Voltage: ");
    Serial.println((float)fetchWord(BATT_SMBUS_VOLTAGE)/1000);
 
    Serial.print("Full Charge Capacity mAh: " );
    Serial.println(fetchWord(BATT_SMBUS_FULL_CHARGE_CAPACITY));
 
    Serial.print("Remaining Capacity mAh: " );
    Serial.println(fetchWord(BATT_SMBUS_REMAINING_CAPACITY));
 
    Serial.print("Temp: ");
    unsigned int tempk = fetchWord(BATT_SMBUS_TEMP);
    Serial.println((float)tempk/10.0-273.15);
 
    Serial.print("Current (mA): " );
    Serial.println(fetchWord(BATT_SMBUS_CURRENT));

    Serial.print("Device Name: ");
    length_read = i2c_smbus_read_block(DEV_NAME, i2cBuffer, bufferLen);
    Serial.write(i2cBuffer, length_read);
    Serial.println("");

    Serial.print("Chemistry ");
    length_read = i2c_smbus_read_block(CELL_CHEM, i2cBuffer, bufferLen);
    Serial.write(i2cBuffer, length_read);
    Serial.println("");

    String formatted_date = "Manufacture Date (Y-M-D): ";
    int mdate = fetchWord(MFG_DATE);
    int mday = B00011111 & mdate;
    int mmonth = mdate>>5 & B00001111;
    int myear = 1980 + (mdate>>9 & B01111111);
    formatted_date += myear;
    formatted_date += "-";
    formatted_date += mmonth;
    formatted_date += "-";
    formatted_date += mday;
    Serial.println(formatted_date);

   // Serial.print("Specification Info: ");
   // Serial.println(fetchWord(SPEC_INFO));
 
    Serial.print("Cycle Count: " );
    Serial.println(fetchWord(CYCLE_COUNT));
 
    Serial.print("Relative Charge(%): ");
    Serial.println(fetchWord(RELATIVE_SOC));
 
    Serial.print("Absolute Charge(%): ");
    Serial.println(fetchWord(ABSOLUTE_SOC));
 
    Serial.print("Minutes remaining for full charge: ");
    Serial.println(fetchWord(TIME_TO_FULL));
 
    // These aren't part of the standard, but work with some packs.
    // They don't work with the Lenovo and Dell packs we've tested
    Serial.print("Cell 1 Voltage: ");
    Serial.println(fetchWord(CELL1_VOLTAGE));
    Serial.print("Cell 2 Voltage: ");
    Serial.println(fetchWord(CELL2_VOLTAGE));
    Serial.print("Cell 3 Voltage: ");
    Serial.println(fetchWord(CELL3_VOLTAGE));
    Serial.print("Cell 4 Voltage: ");
    Serial.println(fetchWord(CELL4_VOLTAGE));
 
   // Serial.print("State of Health: ");
   // Serial.println(fetchWord(STATE_OF_HEALTH));
 
    //Serial.print("Battery Mode (BIN): 0b");
    //Serial.println(fetchWord(BATTERY_MODE),BIN);
 
    //Serial.print("Battery Status (BIN): 0b");
    //Serial.println(fetchWord(BATTERY_STATUS),BIN);
 
    Serial.print("Charging Current: ");
    Serial.println(fetchWord(CHARGING_CURRENT));
 
    Serial.print("Charging Voltage: ");
    Serial.println(fetchWord(CHARGING_VOLTAGE));
 
    Serial.print("Charging Current (mA): " );
    Serial.println(fetchWord(CURRENT));

    Serial.println(".");


 
//-----------------------------------------------------
//Attempt to fetch data again and store it for LCD
//-----------------------------------------------------


  float cellV1(fetchWord(CELL1_VOLTAGE));
  cellV1 = cellV1 / 1000;
  float cellV2(fetchWord(CELL2_VOLTAGE));
  cellV2 = cellV2 / 1000;
  float cellV3(fetchWord(CELL3_VOLTAGE));
  cellV3 = cellV3 / 1000;
  float cellV4(fetchWord(CELL4_VOLTAGE));
  cellV4 = cellV4 / 1000;

    LCD.init(); //This initilasies the LCD Screen  This also currently stops the SMBus Battery data reading
    LCD.backlight();//this turns the backlight on
   

    //LCD.setCursor(0,0);
    //LCD.print("Charge V:");
    //LCD.println(fetchWord(CHARGING_VOLTAGE));
    //LCD.setCursor(0,1);
    //LCD.print("Charge mA:");
    //LCD.print(fetchWord(CHARGING_CURRENT));
   


    LCD.setCursor(0,0);
    LCD.print("C1:");
    LCD.print(cellV1);
    LCD.print(" ");
    LCD.print("C2:");
    LCD.print(cellV2);
 

    LCD.setCursor(0,1);
    LCD.print("C3:");
    LCD.print(cellV4);
    LCD.print(" ");
    LCD.print("C4:");
    LCD.print(cellV4);
   



    delay(100);


 
}
 
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Have you tried just adding a very long delay at the end of the initial code, so that it basically leaves the battery info up on the screen for you to read, using the initial valid data? That's how I initially got the info up on the screen before going for the full AVR reset hack in my code to keep it repeating the cycle...
 
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Have you tried just adding a very long delay at the end of the initial code, so that it basically leaves the battery info up on the screen for you to read, using the initial valid data? That's how I initially got the info up on the screen before going for the full AVR reset hack in my code to keep it repeating the cycle...
When I used your hack it locks up my R3 Uno tighter than a Fart and the orange LED stays on solid. I have to short the reset pins to boot load the bitch haha. I used a wire from Digital output pin 12 and put it to the reset pin, and power cycled it every time. That sucks its very slow, as it has to reboot each time. If I comment out LCD.init() it reads the battery every time in the loop. I think its the LCD i2c stuff. And im an i2c NOOB.

I tried delays and it just does the same thing, but with a delay. hahah.. Any other ideas? as im right stuck and I hate this lol lol.
 
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Messing around more with this project. Think i blew up my R3 Ugh... I had these made up before I saw someone else made something similar. Anyways, can someone measure their battery for me please. Between ground and either SDA and SCL, I have +16v from Bat ground to either pin of SCL or SDA? is this normal? If so that could be why my R3 powered on without the USB plugged in to it. Am I not supposed to hook SCL and SDA directly to the Arduino, I looked back at the pics of the start of the thread and it looks like the other guys had directly connected them?
20170403_221937.jpg 20170403_221913.jpg
 
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OK did some digging more on this, And found this little tidbit. I think the 16v On the SDA and SCL lines is ok.... as long as you dont power on the battery first. Connect up the Arduino to the battery first and then Turn on the battery. Dont HOT install the plug like I did.How to protect my arduino, while hotplugging its power supply and other related electronics

Most important bit is at the end I guess :

If you ever drive an I/O more than a diode drop above or below its power supply rails, the internal ESD protection structure will begin to conduct. The internal structure is only there to keep the part alive during normal handling, i.e. in a factory but not for the situation described above. If the current in this structure is allowed to go high enough, it looks like an SCR and "Latches" up. When latch up occurs the device, like an SCR, will keep conducting as much current as the power supply rails are capable of until the current is removed and usually results in device destruction. The way around this is to limit the current that may flow into a pin, and prevent current from forward biasing the ESD structure: http://www.tayloredge.com/reference/Electronics/EMIESD/InputProtection.pdf
 
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Hi, Cynfab!

I have been playing a little (in fact: a lot ... :) ) with an Arduino Mini Pro and your code just to simulate a Solo Battery, despite beeing an Arduino newbie.
In short: it does'n seems working :(. Putting a scope on the SMbus revealed a strange thing: the Solo mainboard just makes writes to address 0x00h (data 0x01h 0x00h) - see screenshot attached. This reading is repeated every 2 seconds.
Who the hell is on address 0x00h? The battery must be on 0x0b !!! No wonder no one is answering. Am I missing something? I tried two different Solos, 2 different Arduino boards. Solo and Pixhawk up to date (2017) - maybe this is the problem?
Modified code attached (only voltage and current calculation changed due to different sensors).
No access to original battery... yet... so unable to compare the readings :(
Any help will be greatly appreciated!





Here is the code I have been using in my FrankenSolo since last May.
Arduino Nano with an ASC712 current sensor. Measures battery voltage, current & calculates remaining capacity.
It is still a WIP, but works well enough to fly. It assumes that your battery is 5500MAH and is fully charged when you start.
I still plan to estimate starting charge via initial voltage reading and scale as appropriate.

Enjoy... But beware of all issues relating to LiPo batteries. Don't burn down your house or your Solo.
 

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I have successfully compiled the code and program the Atmega to read through the I2C bus using the code in this post. I was able to read several data points but I really don't what all of them mean. Is there a document that explains that.
 
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I have successfully compiled the code and program the Atmega to read through the I2C bus using the code in this post. I was able to read several data points but I really don't what all of them mean. Is there a document that explains that.
Its basic SMBus Battery data? What dont you understand? All the variables are clear, and the output is pretty self explanatory? Can you be a little more specific?
 
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Hi, Cynfab!

I have been playing a little (in fact: a lot ... :) ) with an Arduino Mini Pro and your code just to simulate a Solo Battery, despite beeing an Arduino newbie.
In short: it does'n seems working :(. Putting a scope on the SMbus revealed a strange thing: the Solo mainboard just makes writes to address 0x00h (data 0x01h 0x00h) - see screenshot attached. This reading is repeated every 2 seconds.
Who the hell is on address 0x00h? The battery must be on 0x0b !!! No wonder no one is answering. Am I missing something? I tried two different Solos, 2 different Arduino boards. Solo and Pixhawk up to date (2017) - maybe this is the problem?
Modified code attached (only voltage and current calculation changed due to different sensors).
No access to original battery... yet... so unable to compare the readings :(
Any help will be greatly appreciated!
The way I started was to build a SMB battery reader based of Pdxsteve's work. I got it to read the solo battery, then proceeded to develop the simulator code. When I was able to have both simulators talking to each other I moved to using the real solo. Pullups on sda and sck are necessary. I used a arduino nano, but also had the reader working with an UNO. In my setup it was easy to swap sda & sck and I did often by mistake and of course nothing worked till I got a clue and switched it right way around.
Without a solo battery to compare, it will be hard to debug, and btw it is the pixhawk that is reading the battery data, not the solo's iMx6 companion computer. checkout batt_smbus.cpp for more details.
 
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I was hoping there is a comprehensive list of what the different terminology means. To be more specific (State of Battery,
Battery Mode (BIN),Battery Status (BIN), Cycle Count,) are the ones that I can't figure out. I'd also like a list of units for data collected in the process.

Regards
 
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I was hoping there is a comprehensive list of what the different terminology means. To be more specific (State of Battery,
Battery Mode (BIN),Battery Status (BIN), Cycle Count,) are the ones that I can't figure out. I'd also like a list of units for data collected in the process.

Regards
See if this helps.
 

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Hi, Cynfab!

I have been playing a little (in fact: a lot ... :) ) with an Arduino Mini Pro and your code just to simulate a Solo Battery, despite beeing an Arduino newbie.
In short: it does'n seems working :(. Putting a scope on the SMbus revealed a strange thing: the Solo mainboard just makes writes to address 0x00h (data 0x01h 0x00h) - see screenshot attached. This reading is repeated every 2 seconds.
Who the hell is on address 0x00h? The battery must be on 0x0b !!! No wonder no one is answering. Am I missing something? I tried two different Solos, 2 different Arduino boards. Solo and Pixhawk up to date (2017) - maybe this is the problem?
Modified code attached (only voltage and current calculation changed due to different sensors).
No access to original battery... yet... so unable to compare the readings :(
Any help will be greatly appreciated!

Adress 0x00 is a General Call Adress in SMBus/I²C

Special Addresses and Exceptions - Embedded Systems Academy
 
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The way I started was to build a SMB battery reader based of Pdxsteve's work. I got it to read the solo battery, then proceeded to develop the simulator code. When I was able to have both simulators talking to each other I moved to using the real solo. Pullups on sda and sck are necessary. I used a arduino nano, but also had the reader working with an UNO. In my setup it was easy to swap sda & sck and I did often by mistake and of course nothing worked till I got a clue and switched it right way around.
Without a solo battery to compare, it will be hard to debug, and btw it is the pixhawk that is reading the battery data, not the solo's iMx6 companion computer. checkout batt_smbus.cpp for more details.
Hi, Cynfab!
So as I understood, you have UNO boards for the simulator? - probably I made some mistakes when edited / compiled for the Mini Pro :(
 
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I use both a UNO and a nano at various times for each. THe code I posted was for the nano. pins are probably different on the Mini Pro.
 

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